django重定义authenticate方法

class EmailCheckModelBackend(ModelBackend):
    """
    重新定义authenticate方法
    """
    def authenticate(self, username=None, password=None):
        try:
            user = models.User.objects.get(Q(email=username)| Q(username=username))
            if user.check_password(password):
                return user

        except models.User.DoesNotExist:
            return None